Gyrocompass



Feb. 29, 1944.

' Filed May 6, 1942 o. E. EsvAL v2,342,655

Gmo coMPAss v 2 sheets-sheet' 1 M'RNEY.

Feb.29,1944; 0.5 E53/AL A' 2,342,655

. GYRQ COMPASS V INVENTOR oRLAND E. EsvAL` MNH.

shown in Fig. l.

vairmail Feb. 29,1944 l' auaess 'I Graocoxrass Orland E. Esval, Merrick, N. Y.. assignor to. Sperry Gyroscop'e lompany, Inc., corporationof New York Application May 6, 1942. Serial No. '441,975v

Brooklyn, N. Y., a

s claims. Y (c1. ss-zz's) This invention relates to gyro compass instruments and particularly concerns an electromagnetic coupling means for controlling a free gyro by which the same is givendirection seeking properties.

One of the features ofthe invention is to provvide a coupling meansof this noted character that is simultaneously'effective to damp' the gyro compass instrument. 1 l

Another feature of the invention consists in l the double wound stator of the electromagnetic couple which produces two separate parallel flux fields rotating in opposite directions.

Still a further feature of the invention is contained in the provision of a unitary displaceable inductor member which links the stator and is normally situated in an ineffective position midway between the spaced flux elds of the stator.

Still another feature of the invention' is to provide a coupling means for controlling a Ngyro Iii which provides upper and lower bearings re- Y spectively indicated at II and I2 in which the' trunnions of a vertical ring I3 are journaled. Thev ring is a single part of the conventional free 5 gyro instrument illustratively employed in the drawing to aid in the description of the invention, the instrument further including a rotor bearing frame I4 which is pivotally mounted in the usual fashion between the upwardly extendl0 ing arms of the ring I3. The gyro rotorl is instrument by which the ratio of the torque forces exerted thereby about both th'e horizontal and verticalaxes ofthe gyro remains constant.

A further feature of the invention resides in the provision for stabilizing the stator frame of the instrument by means of a gyro vertical.

-Other featuresgand structural details ofthe.

invention will be apparent from the following description when read in connection with the accompanying drawings, wherein Fig. 1 is a side elevation of the improved gyro compass instrument vwith the casing illustrated in section to show the working parts,

Fig. 2 is a plan view of the form of instrument Fig. 3 is an'enlarged detail plan view-of the gyro unit of the instrument and its control ele-' rig. c is a detail side envauoniuustratmg tn wiring connections employed in the stator unit. Fig. '7 is a detail front view of a modified form of inductor; and

Figs. 8. 9 and '10 are diagrammatic force diamounted to spin on a normal horizontal axis perpendicular to the axis of the frame and is designated'at I5. Anysultable means may be provided to spin the rotor I5, but inasmuch as 5 the present invention is not particularly concerned with this feature, the same has not been specically illustrated. The gyro is consequently provided with verticaland horizontal axes of freedom provided by vertical ring I3, within o which `the rotor bearing frame Il is pivoted on horizontal axis Il', Il. A directional indication is obtained from the disclosed instrument by a vertical compass card I6. which is turned through a crown gear I 1 and meshing bevell gear I8 seelectromagnetic coupling means in the form of a Ta two-part inductive means, one part mounted on the gyroscope and the other part universally and independently mounted, one part being in the form of an inductor and the other atwopart coil member. The inductor member is f shown as rigidly mounted on the frame I 4 in a position to tilt with the same as it moves about its horizontal axis in the ring I3. The inductor element4 is generally indicated at 20, the same being'- suitably :insulated from the frame and a 5 being countrbalanced by means of an adjustable weight 2|. The flux linking portion of themovable inductor element is specically shown in the drawings as formed of four separate rods or ^wires 22 of conducting material which extend 50 outwardly from'the holding plate or base, which grams showing-the manner in which the 'gyro compass is controlled during operation.

With particular reference to Figs. l and 2, a gyro compass constructed to' embody the present is preferablyof insulating material.- To the rear I of such plate the outer ends of each rod are elec- "trically connected or.shortclrcuited by means of cross wires 23. :For the purposes of the present inventive concepts is shown enclosed i'n a casing 65 'invention, the four inductor rods 22 are considcured to the vertical ring I3 of the gyro. A suita ered to be a single inductor element. However, it is pointed out that any suitable member of such flux linking inductors may be employed to obtain any desired torque to eiect precession of the gyro in accordance with the teaching of the present invention.

The neld flux providing coil member linking the inductor is constructed in two separately functioning electrical parts and is employed, in

`the present instance, as the ystator member of the electromagnetic couple. The double `wound stator illustrated is placed on a single frame 24. Two separate and parallel`ux elds are produced by the respective circular coil elements of the stator or spaced fields which include the upper and lower concentric, pole including rings 25 and 26, each having a plurality of inwardly facing poles. The`cores are polyphase wound to produce a moving unidirectional iiuxtfield when energized by a suitable polyphase source I (not shown). Three phase windings are preferably employed, energy being supplied through leads 21, 26 and 29. As shown in Fig. 6, two of the leads between the circular, parallel, coil elements are reversed so that the upperwindings 7 produce, for example, a unidirectionally moving field, as viewed in Fig. 3, which travels in la clockwise direction and the lower windings produce a similar eld which travels in a Acounterclockwisev direction. The normal position of the linking portion 22 of the inductor with respect to the doublewound stator is shown in Fig. 4 in which the same is situated midway between the spaced moving flux fields of the two stators and is consequently not influenced thereby. The sepaiately functioning coil stator members are disposed in parallel planes equidistantly 'spaced -above and below the normal horizontal plane dened by the spin axis of the gyro rotor l5 and the horizontal axis of the rotor bearing frame i4.

The stator frame 24 surrounds the gyro instrument and is universally mounted by means of .trunnions 30' and 3l which extend therefrom,

the trunnions'being suitably journaled in a U- shaped frame 32 which is pivotally supported on a single trunnion 33 perpendicularly situated with respect to trunnions Sil-3l. Trunnion 33 is journaled in a bearing 34 mounted on a post 35 situated within the casingA I0.' As shown, the universally supported stator frame 24 is stabilized in a normally horizontal plane by a gyro vertical instrument situated within the casing I0, as hereinafter described. Alternatively, the stator frame may be kept horizontal by making the same pendulous about its axes oi support.

The gyro verticalinstrument shown employed 'for this purpose is shown as of conventional form and includes a gimbal ring 36 whose aft pivot is provided by trunnion 33 and bearing 34. To provide stabilization about the Atrunnion 36-3I axis of the frame 24, a connecting linkage is employed which includes arms 31, 38 and 39. Arm 39 is rigidly mounted' on an extending portion of one of the athwartship trunnions, 'as indiare midway between the rotating nelds produced by the coil members. As the frame I4 begins to tilt. about its horizontal axis due to rotation of the earth, the frame assumes a position, as shown exaggerated in Fig. 5, in which the inductor 22- comes more Within the influence of the moving field produced by the `upper stator coils on the frame 26. When the instrument is located north of the Equator, the north end of the gyro spin axis tends to turn towards the east and rise asthe earth rotates.l Such a position is shown diagrammatically in Fig. 9, in which the meridian position, with respect to which the gyro spin axis should be maintained parallel, is indicated at 42. The` inductor 22 then links th'e upper rotating flux eld, represented by a line at 43,y the eld moving in the direction indicated by the arrow. A current is consequently induced inthe inductor producing a force between the coupled parts that is at right angles to the inductor where it links the ilux field and is represented by the line designated at F in Fig. 9. The rod 22 is inclined with respect to the ilux eld so that a vertical component Fm and a horizontal component Fd of force F are obtained which' are respectively eective to cause precession in vthe direction indicated by the lines Pm and Pd. The direction of spin of the gyro rotor is shown by the arrow 44. The torque produced by the force Fm is exerted about the horizontal axis of-the rotor frame and causes precessional movement of the vertical ring i3 of the instrument in a direction to move the spin axis of the rotor towards the meridian. The torque produced by the force Fd is exertedv about the axis of the vertical ring i3 and causes precessional movement of the rotor frame i4 in the indicated dlrection to reduce the tilt and thereby damp the movement of the gyro instrument. Due to gyroscopic momentum, the spin axis of the gyro will swing past the meridian to assume a position shown diagrammatically in Fig. 10, wherein the inductor links the lower of the rotating flux lields of the stator as indicated by the straight line 45. This field is traveling in the opposite direction, to the field of the upper coil member ant movements are reversed so that the spin axis of the gyro rotor is caused to again move:

of the stator, as shown by the arrow, and the resultant forces'and precession movement of the gyro instrument caused by the same are shown in a manner similar to the showing of the same in Fig. 9. In Fig. 10, the direction of the resulttowards the meridian 42, and its tilt is reduced, this action continuing until the spin axis of the. rotor comes to rest substantially level and on the meridian.

As shown in Fig.'8, the angle a made between the curved inductor rod 22 and the respective flux elds 43 and 45 is iixed and a constant ratio between the torques respectively imparting direction seeking and damping properties to the instrument is obtained. By changing the angle a, dierent constant ratios of the' simultaneously effective torque effort may be obtained, as de- -sired. When the limiting positions are approached as, for instance, when angle a is made zero, the damping torque is eliminated. Also, if the angle is made substantially 90 degrees, the coupling means is then only effective to eliminate tilt and the instrument becomes a direc.

, tional gyroscope withoutmeridian-seeking properties. The invention contemplates the utilization of the electromagnetic couple described for accanto either or both of the noted purposes, but preferably the angle a is made acute so that both,

direction seeking and damping factors are'simultaneously introduced to control the gyro compass instrument. -I

By curving the inductor rods 22, as shown in Fig. 7, the ratio of the torque'forces exerted about the horizontal and vertical 'axes of the gyro may be varied as desired in. accordance with the extent of inclination of thgyro rotor fra'me about its axis. Another obvious manner`of`varying the strength ofthe torque forces would be to change. the strength of .the respective.ilux elds of the stator.

As many changes could be made in the above construction and many apparently widely' dinerent embodiments of this invention could be made without departing from' the'seope thereof, oit is intended thatI all matters contained in the above description or shown in the accompanying drawings shall. -be interpreted as illustrative and not ,in a limiting sense.

Aas said horizontal axis, and an independently' mounted double wound stator concentric with said inductor. and formed of two, circularly shaped, parallel, coil members which respectively provide. oppositely directed, moving ilux iields, said inductor being normally situated mid-way between said coil members.

2. A gyro compass comprising, in combination,

a gyro having vertical and horizontal axes of free support, a direction indicating element controlled by thegyro, and electromagnetic coupling means consisting of an independently mounted..V

double wound, stator formed of two, circularly shapedfparallel, coil members which provide, oppositely directed, moving nux elds, and a displaceable inductor mounted on said gym linking w either one or the other of said coil members. upon tiltof the gyro, to exert a torque about both the 4 horizontal axis of the gyro to cause a direction:

seeking precessional movement thereof and the 'vertical axis ofthe gyro to cause a damping precessional movement thereof.

3. A gyro compass comprising, in combination.

ing in one direction and said lower coil member being wound to produce a unidirectional flux iield moving in the opposite direction, and means for energizing s'aid stator.

4. A gyr'o compass comprising, .in combination, a gyro including agyro rotor, a frame carrying said rotor for spinning and pivoted for movement about a horizontal axis normalto said spin axisV and on which the rotor is mounted to spin about a. normally horizontal axis, a ring for pivoting said rotor bearing frame about a vertical axis, a direction indicating means controlled by the ring, electromagnetic coupling me'ans consisting of a double wound stator having two parallel,

circularly shaped, coil members concentric of said vertical axis to respectively produce oppositely directed, moving flux fields, independent mounting means for said stator whereby one of the coil members thereof is normally positioned in a. parallel plane above the plane donned by the rotor and rotor irame-.axes of the gyro and the other coil member is positioned below the defined plane, an inductoron said bearing frame linking either one or the other of said coil members, upon tilt of the frame about its axis, to exert a torque about both the axis of the frame to cause a-direction seeking precessional movement of the ring and' the axis of the ring to cause a damping precessional movement'of the frame, and means for energizing said stator. 5. In a gyro compass, a rotor bearing frame mounted in neutral equilibrium for freedom about horizontal and vertical axes, a universally gimballed normally horizontal circular winding surroundingsaid frame and lying substantially in the plane of said horizontal axis, a cooperative member on said frame whereby torque is exerted about the horizontal' axis of said frame upon tilt thereof` about Asaid horizontal axis, and a gyrovertical connected to said circular winding for stabilizing the same.

6. A gyro compass as claimed in claim 5, Wherein' said rwinding and cooperating member are inrounding said gyo compass and lying in the hori.

a gyro including a gyro rotor member, a frame carrying said rotor for spinning and pivoted for I v movement about a horizontal axis normal to said v spin axis,.a ring for pivoting saidlrotor frame about a vertical axis, a direction indicating means'controlled by the ringi electromagnetic coupling means for simultaneously eiecting a direction seeking precession of the -ring and .a damping precession of the frame including a woundto produce a unidirectional flux field moveluded so that upon relative tilt of said frame and winding a torque is exerted on'said frame about both the horizontal and vertical axes thereof, whereby both meridian seeking and damping properties are imparted to the gyro compas.

7. A gyroscopic compass mounted for freedom about vertical and horizontal axes, a two-part electromagneticfinductive' coupling means sur-'- zontal plane of said horizontal axis, one part ofsaid coupling means being mounted on said gyro compass and the other part having an'independen t universal mounting concentric therewith, and

one of said parts comprising an inductor and the other a two-part coil member wound to provide two vertically spaced, parallel, oppositely directed moving linx-fields between which the inductor is normally positioned. whereby, upon relative tilt of said two-part electromagnetic coupling, a torque is exerted on said compass about its horizontal axis.

8. A gyro compass as claimed in claim 7, in

.which one of the parts of said electromagnetic coupling means lies at an acute angle to the horizontal, whereby the resulting torque on the gyrascope has both horizontal and vertical components to impart both meridian-seeking and damping properties to the compass.

n ORLAND E. EBVAL.

cnnnncAm com'cmon. A Patent No. 2,512,655. hmm 29 .19Min omun a. EsvAL.

It 1s hereby certified that error appears in the printed specification of the above numbered patent requiring correction ne'fcllws: Page 5, second column,- line 145-1411., claim 6, for *inciuded* reid 1nc1ined g and that \the said Letters Patent should be rend with this correction therein Vthat the enne muy gonfom to the regard of the case inthe Pitent Office.

S19-led. and sealed this 16th da; of hay', A`. :13) 191m..

I Leslie Frazer (Seal) Loting Com'miesidner of Pdtente. 

